The present invention relates to a wrap spring clutch. The wrap spring clutch is configured with double-ended spring press.
A wrap spring clutch is a well-known mechanism for alternately transferring rotation from an input rotation source to some output and then detaching the source of input rotation from the output. The wrap spring clutch has an input, and output with a wrap spring coupled between them. The wrap spring is wrapped open or wrapped down to connect and disconnect the input to the output, thereby engaging and disengaging the clutch. This invention relates to spring clutch mechanisms and to improved means for anchoring the ends of the helical clutch spring.
Attachment between the wrap spring the input or the output in spring clutch mechanisms has previously been accomplished by several other methods. In one, a tab or tang extending either axially or radially from an end turn of the helical coil spring is inserted into a slot or cavity in the input or output transmitting member. In another method, the several end turns of the wrap spring are frictionally secured to the input or output transmitting drum, e.g. by reducing the diameter of the turns, or by increasing the number of contacting coils or the diameter of the drum. A further method involves the placing of a separate compressible split ring about the several end turns of the spring.
The shaping of the spring wire to provide a partially constricted diameter or an additional tang involves added expense and production requirements. An axial tang requires an axial cavity and limits desirable reduction in thickness of the member receiving the tang. A spring restrained by a tang is subject to “humping”, a condition in which the adjacent coils do not return fully to their initial diameter and so cause an alteration of the “at rest” position of clutch-connected mechanism. The incorporation of a compressible split ring involves additional expense both in components and in assembly, and increases space requirements.